* Oxygen as an element: Oxygen (O) is an element, meaning it's a pure substance made up of only one type of atom. So, in a single oxygen atom, there's only one atom.

* Oxygen as a molecule: Oxygen commonly exists as a diatomic molecule (O₂), meaning two oxygen atoms are bonded together. In a single oxygen molecule, there are two atoms.

So, it depends on what you're asking about:

* Individual Oxygen atom: 1 atom

* Oxygen molecule (O₂): 2 atoms